My situation is very similar to yours. I am my husband's caregiver. He was diagnosed with MM in 2015 and had a stem cell transplant in 2016 followed by 2 years of revlimid.
In early 2023 his platelet counts dropped below 50. A bone marrow biopsy showed med/high risk MDS. His consultant referred to it as "secondary MDS" as it seems likely to be a result of the chemo he received in preparation for the stem cell transplant - which was successful as it put the MM into remission and gave him excellent quality of life for the next 7 years.
Treatment for the MDS to date has been 7 day cycles of Vidaza every 21 days over 11 months. His platelets recovered reasonably well (80-160), HB was stable around 11, but neutrophils remained persistently low ranging from 0.09 to 1.2 at best. he used gcsf injections to boost his neutrophils on a couple of occasions. In November following a fever he was hospitalised for neutropenic sepsis. Neutrophils were low for treatment in December and we are awaiting another bone marrow biopsy before next steps are planned. In the meantime platelets have dropped to 4 - with no increase following 2 platelet transfusions, HB around 6 to 8 with no change following 2 transfusions and neutropenia persists. We await news and an updated treatment plan.